An ad hoc network is under investigation that is configured by terminals wirelessly connectable to each other and that can execute communication without a wireless Local Area Network (LAN) access point, etc.
For example, a wireless communication system has been disclosed that transmits and receives packets between a transmission source terminal and a destination terminal through at least one relay terminal in an ad hoc network including plural terminals, where the transmission source terminal broadcasts a path request packet to the destination terminal; the relay terminal additionally writes the available band and the address of the relay terminal in the path request packet, and subsequently broadcasts the path request packet; the destination terminal selects a path to communicate packets to/from the transmission source terminal based on the available band additionally written in the path request packet, and notifies the transmission source terminal of the path selected; and the transmission source terminal sets the path reported by the destination terminal as a path to transmit and receive packets to/from the destination terminal (see, e.g., Japanese Laid-Open Patent Publication No. 2005-347850).
A technique has also been disclosed, where a first communication path from a wireless terminal “A” through a wireless terminal “C” to a wireless terminal “E” and a second communication path from the wireless terminal A through the wireless terminal C to a wireless terminal “G” are formed. In this state, when a communication path is constructed between the wireless terminal A and a wireless terminal “H”, and a wireless terminal “D” receives a path request message from the wireless terminal C having a high load, before receiving a path request message from a wireless terminal “F” having a low load, the path request message from the wireless terminal F having a low load is selected. Consequently, rather than the path with the least number of hops from the wireless terminal A through the wireless terminal C and the wireless terminal D to the wireless terminal H, a communication path that has one more hop, excludes the wireless terminal C whose processing load is high, and is from the wireless terminal A through the wireless terminal B, the wireless terminal F and the wireless terminal D to the wireless terminal H is established (see, e.g., Japanese Laid-Open Patent Publication No. 2006-211375).
However, with the above conventional techniques, in the ad hoc networks, the state of the networks vary continuously due to fading, etc., and therefore, a problem arises in that stable communication cannot be executed. When path searches are frequently executed to enable an optimal path to be selected according to the varying state of the network, another problem arises in that the wireless resources are pressured.